I think it would be nice if we could have the catalogue be able to be sorted by where you can get items. For example I was only missing one item in the legwear section (that's not from the welcome amiibo items) and I was assuming it was from kicks but thought it might possibly be from Gracie instead. So if things could be organized by where you get them it would help a lot for filling things out since you wouldn't have to go searching elsewhere for the information.
(The Golden Rule)
Treat others the way you want to be treated. :)